import React, { Component } from 'react'
import './index.css'

export default class Footer extends Component {

  //全选checkbox的回调
  handleCheckAll=(event) => {
    this.props.checkAllTodo(event.target.checked)
  }

  //清除所有完成任务的回调
  handleClearAllDone=() => {
    this.props.clearDoneTodo()
  }
  render () {
    const { todos } = this.props;
    //已完成统计
    const doneCount = todos.reduce((pre,todo) => pre+(todo.done? 1:0),0)
    //总计
    const total = todos.length;
    return (
      <div className="todo-footer">
        <label>
          <input type="checkbox" onChange={this.handleCheckAll} checked={doneCount === total && total !== 0? true:false }/>
        </label>
        <span>
          <span>已完成{doneCount }</span> / 全部{total}
        </span>
        <button className="btn btn-danger" onClick={this.handleClearAllDone}>清除已完成任务</button>
      </div>
    )
  }
}
